Various strains of Chlamydiae psittaci and C. trachomatis will be grown in L cells, HeLa cells, and mouse peritoneal macrophages to study and compare the attachment, ingestion, and intracellular fate of the chlamydiae by host cells and the effect on host cells of phagocytosing these parasites. BIBLIOGRAPHIC REFERENCES: Moulder, J.W., Hatch, T.P., Byrne, G.I., and Kellog, K.R. 1976. Immediate toxicity of high multiplicities of Chlamydiae psittaci for mouse fibroblasts (L cells). Infect. Immun. 14: 277-289.